1. Field of the Invention
The field of the invention relates generally to transmissions, and more particularly the invention relates to continuously variable transmissions.
2. Description of the Related Art
The present invention relates to the field of continuously variable transmissions and includes several novel features and inventive aspects that have been developed and are improvements upon the prior art. In order to provide an infinitely variable transmission, various traction roller transmissions in which power is transmitted through traction rollers supported in a housing between torque input and output disks have been developed. In such transmissions, the traction rollers are mounted on support structures which, when pivoted, cause the engagement of traction rollers with the torque disks in circles of varying diameters depending on the desired transmission ratio.
However, the success of these traditional solutions has been limited. For example, in one solution, a driving hub for a vehicle with a variable adjustable transmission ratio is disclosed. This method teaches the use of two iris plates, one on each side of the traction rollers, to tilt the axis of rotation of each of the rollers. However, the use of iris plates can be very complicated due to the large number of parts that are required to adjust the iris plates during transmission shifting. Another difficulty with this transmission is that it has a guide ring that is configured to be predominantly stationary in relation to each of the rollers. Since the guide ring is stationary, shifting the axis of rotation of each of the traction rollers is difficult.
One improvement over this earlier design includes a shaft about which a driving member and a driven member rotate. The driving member and driven member are both mounted on the shaft and contact a plurality of power adjusters disposed equidistantly and radially about the shaft. The power adjusters are in frictional contact with both members and transmit power from the driving member to the driven member. A support member located concentrically over the shaft and between the power adjusters applies a force to keep the power adjusters separate so as to make frictional contact against the driving member and the driven member. A limitation of this design is the absence of means for generating an adequate axial force to keep the driving and driven members in sufficient frictional contact against the power adjusters as the torque load on the transmission changes. A further limitation of this design is the difficulty in shifting that results at high torque and very low speed situations as well as insufficient means for disengaging the transmission and coasting.
Therefore, there is a need for a continuously variable transmission with an improved power adjuster support and shifting mechanism, means of applying proper axial thrust to the driving and driven members for various torque and power loads, and means of disengaging and reengaging the clutch for coasting.
The systems and methods have several features, no single one of which is solely responsible for its desirable attributes. Without limiting the scope as expressed by the claims that follow, its more prominent features will now be discussed briefly. After considering this discussion, and particularly after reading the section entitled xe2x80x9cDetailed Description of the Preferred Embodimentsxe2x80x9d one will understand how the features of the system and methods provide several advantages over traditional systems and methods.
In one aspect, a continuously variable transmission is disclosed having a longitudinal axis, and a plurality of speed adjusters. Each speed adjuster has a tiltable axis of rotation is located radially outward from the longitudinal axis. Also provided are a drive disk that is annularly rotatable about the longitudinal axis and also contacts a first point on each of the speed adjusters and a support member that is also annularly rotatable about the longitudinal axis. A bearing disk is provided that is annularly rotatable about the longitudinal axis as well, and at least two axial force generators. The axial force generators are located between the drive disk and the bearing disk and each axial force generator is configured to apply an axial force to the drive disk.
In another aspect, a bearing disk annularly rotatable about the longitudinal axis is disclosed along with a disengagement mechanism. The disengagement mechanism can be positioned between the bearing disk and the drive disk and is adapted to cause the drive disk to disengage the drive disk from the speed adjusters.
In yet another aspect, an output disk or rotatable hub shell is disclosed along with a bearing disk that is annularly rotatable about the longitudinal axis of the transmission. A support member is included that is annularly rotatable about the longitudinal axis as well, and is adapted to move toward whichever of the drive disk or the output disk is rotating more slowly.
In still another aspect, a linkage subassembly having a hook is disclosed, wherein the hook is attached to either the drive disk or the bearing disk. Included is a latch attached to either the drive disk or and the bearing disk.
In another aspect, a plurality of spindles having two ends is disclosed, wherein one spindle is positioned in the bore of each speed adjuster and a plurality of spindle supports having a platform end and spindle end is provided. Each spindle support is operably engaged with one of the two ends of one of the spindles. Also provided is a plurality of spindle support wheels, wherein at least one spindle support wheel is provided for each spindle support. Included are annular first and second stationary supports each having a first side facing the speed adjusters and a second side facing away from the speed adjusters. Each of the first and second stationary supports have a concave surface on the first side and the first stationary support is located adjacent to the drive disk and the second stationary support is located adjacent to the driven disk.
Also disclosed is a continuously variable transmission having a coiled spring that is positioned between the bearing disk and the drive disk.
In another aspect, a transmission shifting mechanism is disclosed comprising a rod, a worm screw having a set of external threads, a shifting tube having a set of internal threads, wherein a rotation of the shifting tube causes a change in the transmission ratio, a sleeve having a set of internal threads, and a split shaft having a threaded end.
In yet another aspect, a remote transmission shifter is disclosed comprising a rotatable handlegrip, a tether having a first end and a second end, wherein the first end is engaged with the handlegrip and the second end is engaged with the shifting tube. The handlegrip is adapted to apply tension to the tether, and the tether is adapted to actuate the shifting tube upon application of tension.
These and other improvements will become apparent to those skilled in the art as they read the following detailed description and view the enclosed figures.